6 Beauty Mysteries, Solved

Mass outlets are definitely starting to offer more try-before-you-buy opportunities. Target has sampling stations for three of its new makeup lines, and Ulta lets you try on Bare Escentuals and Smashbox makeup. If your local drugstore hasn't yet implemented sampling, "the smartest thing to do is to choose colors in the tones you already know work for you," says Los Angeles makeup artist Napoleon Perdis. You may get a second chance to get it right: CoverGirl will let you swap its new Simply Ageless Foundation ($14, drugstores) for a closer match at any store where it's sold. And many drugstores, including CVS, will take back or at least exchange makeup  even if it's been opened.

What can I do to look less tired?

Sleepless nights can remain your secret, thanks to an innovative product called a skin brightener. A distant cousin of bronzers, liquid brighteners  such as Almay Face Brightener ($12.50, drugstores)  come in skin-tone-matching shades like peach and nude that create a subtle, not sparkly, luminosity. To apply, layer a thin coat all over your face before foundation, or dab it just beneath the brow or on top of the cheekbones. Hide dark undereye circles with an eye brightener like Peter Thomas Roth Anti-Aging Eye Illuminator ($28, qvc.com).

How much time should I give a face moisturizer to work before I give up on it?

The answer depends on the special effects you're after. It can take just two to four weeks to see subtle smoothing benefits with anti-aging moisturizers and serums containing peptides, antioxidants, alpha hydroxy acids, and vitamin A derivatives. Sunspots are more stubborn; they may require up to three months to fade using hydroquinone and other skin lighteners. As a general rule, dermatologists recommend you give all creams at least 90 days to work, unless they are irritating your skin. "It takes time for a product to change the skin's underlying process and make it healthier," says Helene R. Rosenzweig, M.D., assistant clinical professor of dermatology at UCLA. If, after 90 days, you're still seeing the same old skin, that's a signal to retool your regimen.

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